Lack of sound when rendering instrument tracks

I have a problem with rendering several of the tracks in a project.

In some cases, I also do not hear sound from the instrument tracks before rendering. I have sometimes solved this by pressing “Stereo out” under “Routing” in the mixer (even if “Stereo out” is already selected.)

Even if I do not get sound from the track, nor if I try to play notes from the keyboard, I get sound if I click with the mouse on the selected notes in the key editor.

In other cases, I hear sound from the instrument track, without success with the rendering.

In the project I have split the drum track into different tracks (Dissolve part). I could render most of the tracks, but not all. Attaches a picture of an attempt at rendering - see track 52. The first event has been rendered without any sound (and the event in the instrument track is not muted, as I have set by default). Before I rendered, I copied the event and put it a little further to the right in the same track. Then one of the tones in the event was rendered, while the others did not join.

Any ideas?